1. Field of the Invention
The present invention relates to a magnetic head and a magnetic recording apparatus provided with the same.
2. Description of the Related Art
Hitherto, a magnetic recording apparatus has been known as one type of information recording equipment for a personal computer or the like.
The magnetic recording apparatus has a plurality of discoid magnetic disks rotatably provided on a chassis, and magnetic heads provided on the front side or the back side of the magnetic disks such that they are free to relatively move with respect to the magnetic disks (magnetic recording mediums). These magnetic heads are respectively supported by bases through the intermediary of long and narrow load beams shaped like triangular plates and arms, the bases being rotatably supported on the chassis. In such a magnetic recording apparatus, as the bases rotate angularly about a rotating shaft, the magnetic head relatively moves in the radial direction with respect to the magnetic disk so as to read magnetic information at a desired position on a magnetic disk or to write magnetic information at a desired position on a magnetic disk.
FIG. 9 is a perspective view showing a contact start stop (CSS) type magnetic head having its recording medium opposing surface facing upward. FIG. 10 is a plan view showing the magnetic head observed from its recording medium opposing surface.
A magnetic head 102 is primarily constructed of a plate-like slider body 111 formed of a nonmagnetic material and a magnetic core 112 that is provided on one end portion of the slider body 111 and has a coil.
In the slider body 111 of the magnetic head 102, the side opposite from the side where the coil is provided is defined as a leading side 113 on the upstream end in the rotational direction of a magnetic recording medium. The side where the coil is provided is defined as a trailing side 115 on the downstream end in the rotational direction of the magnetic recording medium.
A center pad 125 is formed at the center of the width of the trailing side 115 of the slider body 111, the magnetic core 112 being embedded in the center pad 125. Side pads 126 are individually formed on both ends of the trailing side 115 of the slider body 111 such that they are located on both sides of the center pad 125. In the conventional magnetic head 102, an amount of lift is controlled primarily by means of the center pad 125. For this reason, the center pad 125 is formed such that its surface facing the recording medium has a larger area than that of either of the side pads 126. The side pads 126 and 126 are auxiliary pads for the center pad 125, and restrain teetering in the rolling direction or in the direction of the width of the slider body.
The center pad 125 further has a first rear pneumatic bearing surface 125a in which the magnetic core 112 is embedded, and a front stepped surface 125b formed to be lower than the first rear pneumatic bearing surface 125a. The provision of the front stepped surface 125b allows an airflow to smoothly run from the front stepped surface 125b to the first rear pneumatic bearing surface 125a via a front wall surface 125c while the magnetic recording medium is rotating. Thus, the airflow acts on the first rear pneumatic bearing surface 125a to produce a high positive pressure on the first rear pneumatic bearing surface 125a. 
Each side pad 126 has a second rear pneumatic bearing surface 126a and a front stepped surface 126b formed to be lower than the second rear pneumatic bearing surface 126a. 
A center rail 121 is formed on the end of the leading side 113 of the slider body 111. The slider body 111 further has side rails 122 and 123 extending from both ends of the center rail 121 toward the trailing side 115. The center rail 121 has a front pneumatic bearing surface 121a, a front stepped surface 121b formed to be lower than the front pneumatic bearing surface 121a, and a side stepped surface 121c extending from both ends of the front stepped surface 121b toward the trailing side 115. Side rails 122 and 123 are flush with the front pneumatic bearing surface 121a of the center rail 121. The front pneumatic bearing surface 121a of the center rail 121, the first rear pneumatic bearing surface 125a of the center pad 125 and the second rear pneumatic bearing surfaces 126a of the side pads 126 are all flush. A pair of anti-adhesion pads 129 formed to be taller than the front pneumatic bearing surface 121a is provided on both sides of the front stepped surface 121b. Furthermore, a pair of anti-adhesion pads 130 that is taller than the front pneumatic bearing surface 121a is formed on the side stepped surfaces 121c. 
A plurality of pairs of anti-adhesion pads 131, that are taller than the side rails 122 and 123, is provided on a recording medium opposing surface 111a between side rails 122 and 123.
In the magnetic head 102 having the construction described above, as shown in FIG. 11, when an airflow A is generated as a magnetic recording medium 100 rotates, the airflow A moves from the leading side 113 to the recording medium opposing surface of the slider body 111 and acts on the front pneumatic bearing surface 121a of the center rail 121. This causes the front pneumatic bearing surface 121a to be subjected to a positive pressure. The airflow A further acts on the second rear pneumatic bearing surfaces 126a, 126a of the side pads 126, 126, and the first rear pneumatic bearing surface 125a of the center pad 125, causing the first rear pneumatic bearing surface 125a and the second rear pneumatic bearing surfaces 126a, 126a to be subjected to a positive pressure. This allows the slider body 111 to levitate from the front or back surface of the magnetic recording medium 100 and fly so as to read magnetic information from the magnetic recording medium 100 or write magnetic information into the magnetic recording medium 100 by the magnetic core 112 while it is flying. Reference character B in FIG. 11 denotes the direction in which the magnetic recording medium 100 rotates.
In the conventional magnetic head 102, however, the amount of lift of the slider body 111 diminishes with a drop in air pressure, as illustrated by the two-dot chain line in FIG. 11, and spacing H between the magnetic core 112 and the magnetic recording medium 100 diminishes accordingly. This has been posing a problem in that the magnetic core 112 may come in contact with the magnetic recording medium 100, causing the magnetic core 112 to deteriorate. Especially in the case of the magnetic head 102 having the structure shown in FIGS. 9 and 10, the positive pressure applied to the center pad 125 in which the magnetic core 112 is embedded is the highest, and hence the center pad 125 is most likely to be subjected to changes in air pressure. This problem is apt to occur when the number of revolutions of the magnetic recording medium 100 changes or an impact or load is applied from outside during a loading operation in which the magnetic head 102 is brought closely to the magnetic recording medium 100 and then levitated or during a seeking operation in which the magnetic head 102 is moved beyond the magnetic recording medium 100.